TO THE READERS. 



The present volume will complete the Handbook of Physiological Botany, which, 

 since its commencement in 1865, has been edited by the late Prof. Hofmeister. As 

 stated in the Preface to Vol. I, the plan of the book was drawn up in the year 1861, 

 and the sections, which were to be treated according to the state of the science at 

 that time, were distributed into four volumes, and among six contributors. Arrange- 

 ments were made beforehand, so that the Volumes might be expected to appear in 

 quick succession. Two of the contributors retired at the outset, so that, in the year 

 1866, the fourth volume ha\ang first appeared, and then the first section of the 

 second, the programme in the Preface of Vol. I. assigned all the volumes to four 

 contributors, and those still remaining to three. Of these another subsequently 

 retired. Nevertheless, the undertaking was not given up, the preparation of the 

 remaining parts being undertaken by Hofmeister and by the author of this volume. 



At the beginning of last year Hofmeister was attacked by severe illness, to 

 which he succumbed on the 12th of January of this year. After his death the 

 question of the fate of the Handbook presented itself to the surviving contributors. 

 Among the papers of the deceased were found, it is true, drafts and beginnings of 

 the parts he had undertaken. But they have so much the character of incomplete 

 sketches and fragments, that it was obvious to the undersigned that their publication 

 would neither answer the purpose of the Handbook, nor the intentions of their 

 author. The case standing thus, the remaining parts would have to be undertaken 

 by another contributor. Supposing some one to be ready at once, he would have 

 to begin on his own account at the beginning, and the continuation of the 

 Handbook would at best be delayed for years. Nevertheless, if there were a real 

 want, the attempt to continue it would be made. But, in the sixteen years which 

 have passed since the Handbook was planned, the position of our Science has 

 altered. In face of the Literature of to-day, a new work comprising ' the INIor- 

 phology of the Vascular Cryptogams,' and ' the Sexual Reproduction of the 

 Phanerogams,' can be dispensed with, while a separate treatment of the 'Algae,' as 

 at first intended, is hardly possible. On these grounds it has been determined to 

 close the Handbook. As it stands at present, it is arranged as follows : — 



Vol. I. I St Part. ' Die Lehre von der Pfianzenzelle.' By W. Hofmeister. 



2nd Part. ' Allgemeine Morphologic der Gewachse.' By the same author. 



Vol. II. * JNIorphologie und Physiologie der Pilze, Flechten und Myxomyceten.' 

 By A. de Bary. 



Vol. III. ' Vergleichende Anatomic der Vegetationsorgane der Gefasspflanzen.' 

 By the same author. 



Vol. IV. ' Experimentalphysiologie der Pflanzen.' By Julius Sachs. 



A. DE BARY. J. SACHS. 

 SrRASSBURG AND WuRZBURG, June, 1877. 



